text:
What is the difference between Angle of Incidence (AoI) and Angle of Attack (AoA)?
Following discussion here, I am still confused about the difference between AoI and AoA. As I read in many references and watched in many YouTube videos especially this one:
1). AoI is tje angle between the longitudinal axis and the chordline as per design/manufacture. It says normally AoI designed/manufactured is six degrees. AoI remains constant as it is fixed relative to the fuselage.
2). AoA is the angle between the chordline and the RELATIVE AIRFLOW. AoA changes in flight.

My confusion is with the meaning of the RELATIVE AIRFLOW. This phrase confuses me. In my opinion, airflow produced by the propeller or the turbines flows parallel to the longitudinal axis, or at least it has fixed angle, also as per designed too.
To avoid a repetitive question, I want to give this situation.
1). During take off of an airplane, from the airplane start moving until it left the ground, what is the RELATIVE AIRFLOW?
2). After the airplane takes off and during climb, what is the RELATIVE AIRFLOW?
3). During level flight (cruise with constant altitude), what is the RELATIVE AIRFLOW?
4). During approach to land until touching ground, what is the RELATIVE AIRFLOW?
What is actually that AIRFLOW?
I apologize if there are too many questions. It is actually just one. Just to make sure that you will not confuse to read and I will not get confused to read your explanation as product of unclear question.
Before I post this question, I have search if someone have posted previously. But I didn't find the same question.

the term you want is "chord" not "cord"

Thank you have corrected the error. Apologize for the mistake.

Angle of Incidence is fixed by the designer of the aircraft. It does not change in flight.
Angle of Attack is the angle between the chordline of the wing and relative airflow during flight.

That is definitely something that changes during operation of the aircraft in flight. Consider slow flight, for example. You reduce power and raise the nose to reduce airspeed. The direction of the airflow remains the same, but the angle between the airflow and the wing chordline, the Angle of Attack, increases. Raise the nose too much (and hence increase the AoA), and the airflow will separate from the top of the wing and you will stall.
On aircraft like Cessna trainers, the stall warning is a very basic indicator of Angle of Attack, to warn you when you are about to stall.

More advanced Angle of Attack indicator systems use a vane to measure the angle of the relative airflow, and give you more information about AoA.

I have heard like your explanation, but I refused to admit it. As you said, "Consider slow flight, for example. You reduce power and raise the nose to reduce airspeed. The direction of the airflow remains the same, but the angle between the airflow and the wing chordline, the Angle of Attack, increases," so can I say that the AoA is result of that action are taken, not vice versa that the airplane position (nose raised and air speed reduce) due to the AoA changed by the pilot? That's very different which is result and which one is the taken action.

To avoid misunderstanding, I have to correct my sentence above. That should be I have heard like your explanation, but I refused to admit it. But now I admit it.....

Your understanding is incorrect. AOA changes because of actions the pilot takes.

Is any widget in cockpit to set the AoA? I.e: the pilot set the AoA to 11, which it will give direct change to the AoA rather than change the airspeed to meet the AoA?

Not to my knowledge. An AoA is generally considered a passive (though highly useful) indicator. In most aircraft with modern autopilots the pilot selects airspeed and rate of descent or climb, not AoA. Good question, though, and I can see why you asked it. :)

Yes, that actually my question.

Ok, then please accept my answer to your original question. :)

In my opinion, airflow produced by the propeller or the turbines flows parallel to the longitudinal axis, or at least it has fixed angle, also as per designed too.

True, but not something to really worry about.  Turbines/turbofans are not normally mounted ahead of the wings.  Propellers may be ahead of the wing, but most of the airflow over the wing will be in areas not directed by the propeller.  So for consideration here, I will ignore any effects from propellers or other engines.
The RELATIVE AIRFLOW is a description of how the air moves by the airplane (from the point of view of the airplane).  For an airplane that is level in pitch, not changing altitude, in still air, the relative airflow will be from front to back.  Think of having a ribbon on the end of a stick next to the plane.  The ribbon is pulled by the relative airflow (or often, the "relative wind") and shows exactly the angle.  It takes into account the actual movement of the air, and the movement of the craft through the air.

During take off of an airplane, from the airplane start moving until it left the ground, what is the RELATIVE AIRFLOW?

Technically this depends on the actual wind at the ground.  But assuming winds are light and there's nothing odd like a microburst, then the relative wind is exactly opposite the movement of the aircraft.  The aircraft is moving down the runway, so the relative airflow is along the runway.  The angle to the relative airflow depends on the angle of the craft.  It might be rolling at various pitch angles.
All your other questions are the same.  The relative airflow depends on how the air is moving (are there updrafts?  Downdrafts?) and how the plane is moving through the air.   A plane climbing through still air will see relative air moving at a downward angle compared to the horizon.  A plane descending through still air will see relative air moving at an upward angle compared to the horizon.

How about what is explained by @Juan-Jimenez above, the airplane direction is not always parallel to the wind generated by the propeller or to the longitudinal axis? As he said, in flight control, there is situation that power is reduced so nose is pitching up air speed also reduced. This situation makes the plane is moving horizontal but wind flow from the propeller will not parallel to the longitudinal axis. I am not sure by what condition such action will be taken, but such that action is taken.

Yes, the flow from the propeller may be in a different direction.  But so little of that flow hits the wing that we tend to ignore it, and focus on the airflow based only on the airplane's movement through the air.

OK, thank you for your great explanation. Your kind to comment have helped me understand what is confusing me quite long time.


text:
How to calculate on ground aircraft yaw rate knowing the longitudinal speed and inferred yaw angle
Please consider the following scenario:

a generic aircraft is on-ground taxing at 50 feet per second (~15.25 m/s, ~29.5 knots)
The pilot inferred 20 degrees of yaw

How can I calculate the yaw rate of the aircraft? Do I have enough information to calculate it?

Welcome to Stack Exchange! I've never heard the term "inferred yaw angle" before; what does that mean? What do you mean by "the pilot inferred 20 degrees of yaw"?

Do I have enough information to calculate it?

No.
Yaw rate is $rad/s$. You have an angle, $rad$ (or degrees), and you have a linear speed, in $m/s$.
You cannot obtain a $rad/s$ value from these two data points.
You need the time interval over which the change in yaw has been observed.

Hi Federico, unfortunately I haven't got that time interval but I was wondering if there is a way to estimate it. For example if the aircraft system is considered as an ideal kinematic model then: yaw rate = (longitudinal speed)/(nose gear to COG distance + MG to COG distance) * tan(yaw angle).  Sorry I don't know how to write the equation in the correct forum format!

@AlexMcfly Hi. no, also in that case you would be missing variables, in particular the nose wheel deflection. and if you would like to be precise, the friction coefficient of the wheel with the ground, at a minimum.

source: Stack Exchange

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

sort: votes


text:
FIS-B Product Registry Location
I'm a software engineer that's interested in decoding raw FIS-B data. DO-267A (E.1) points me at http://fpr.tc.faa.gov/default.asp as the location of the FIS-B Product Registry. However, I have been unable to connect to this website the last 2 days. Does anyone know if this is still the correct site? Is the data hosted anywhere else?

I have been unable to determine if the Product Registry has been formally relocated or replaced. However, I was able to find all of the relevant information in DO-358A. It wouldn't surprise me if this has become the de facto Product Registry, replacing the FAA website.

all_licenses: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/


text:
Lufthansa Pilots: Are you doing empty flights to keep slots?
It's not about judging LH or any other airline for doing this, I fully understand. I'm asking because I want to be sure not to have a bad opinion of E.U legislation before I have the facts.
If you work for Lufthansa or another major European carrier, are you doing empty flights currently to keep slots?
Public news is inconclusive:
https://www.handelsblatt.com/unternehmen/handel-konsumgueter/luftfahrt-18-000-fluege-ohne-passagiere-das-steckt-hinter-dem-streit-um-die-leerfluege-der-lufthansa/27967268.html?ticket=ST-2091922-HdBZLvRVYbKhhg9DeFTU-ap1
Are the flights happening or is this just a warning?

related, if not duplicate https://aviation.stackexchange.com/q/76743/1467

"I'm asking because I want to be sure not to have a bad opinion of E.U legislation before I have the facts.". You might want to tell which regulation you're talking about. This one,  EEC 95/93, clearly states airports (or States) are responsible for slot allocation, even if recommendations for harmonization are provided: A Member State shall be under no obligation to designate any airport as schedules facilitated or coordinated save in accordance with the provisions of this Article.

Carsten Spohr (CEO of Lufthansa) said in an interview with FAZ last December:

But we have to make 18,000 extra, unnecessary flights over the winter just to secure our take-off and landing rights.

(faz.net, translated from German)
Two days ago, a Lufthansa spokesman told the dpa (German Press Agency):

A part has already been completed, now there are still 11,000 flights that Lufthansa would like to avoid, as a spokesman told dpa. Currently, around 100 commercially unnecessary, almost empty flights are operated in the group every day [...]

(merkur.de, translated from German)
This implies that about 7,000 of these flights have already happened. However, "almost empty" does not mean completely empty. You can buy tickets for these flights, but not enough tickets are sold to make these flights economically viable. The EU commission said:

We have no indication that Lufthansa is operating empty legs to secure slots.

(merkur.de, translated from German)

I suppose they'll also take some mail/cargo; the amount of that didn't decline much.

I read now the merkur.de references.. it sounds as if its "word against word"?

Cargo should be even more.

My understanding is, that LH flies mostly as regularly planned but the planes are not full. Good for passengers which have more options, bad for earnings and sustainability. I’ve seen multiple times full planes and planes with a lot free seats. The slots rules seem to enforce - as a side effect - a basic service requirement similar to the US? But not intentional?


text:
Where can I find the turn radius on the ground for the Piper Seminole?
I meant to be doing a quiz for a class and one of the questions is asking for the turn radius of the Piper Seminole. However I cant find it anywhere in the POH.
Do you know where I can look?

33.0 ft From pivot point to wingtip, it is in the POH page 1-2

Welcome to Av.SE


text:
How much water does the Emirates A380 carry in order to provide onboard showers?
Do you realize that we are living in a world where you can get on an airliner and disembark cleaner than when you got on?
Video: Shower in A380 First Class
This just blows my mind.
How much water does the Emirates A380 carry in order to provide onboard showers?

In addition to Pondlife's answer, I am contributing some more details.
Airbus 380 has room (see page 250) for potable water tanks which can be added to existing on-board water capacity for showers etc.
As we know, the showers aren't available for everyone but only for first class, which is probably less than 5% of the total number of passengers, so the water usage is not tremendously huge.
Waster consumption and shower duration is also controlled. Franke makes the showers for Emirates and states:

Low water consumption of less than 5 litres per minute

When 75% of the allowed shower duration is consumed, it shuts down and you have to turn it on again for the remaining 75 seconds.
Here is a first hand account (including video) of a passenger enjoying the spa.

to conclude, 5 minutes at 5 liters per minute per 14 first class seats makes a required amount of 5514 = 350 liters. Add something to have a spare and for the cleaning in-between-showers. (comment updated with correct figures)

@Federico Wow. Fourteen people showering once each is equivalent to one person showering daily for two weeks. So each of us uses a third of a ton of water every two weeks just having showers.

@DavidRicherby assuming everyone makes showers that are 5 minutes long or less.

@DavidRicherby And assuming that our usual landside showers have a similar water consumption. My flow-through heater has 18 kW and should be able to heat roughly 18 ltr/min, which would make me consume around 180 ltr. (and 3 kWh) on my usual 10-minute shower, which is more than a ton per week. I have heard that others bought a 24 kW heater, since their 18 kW model did not have enough power. That was a real WTF moment...

570 litres, apparently:

To cater for the showers, the airline's 489-seat A380s are fitted with
  two optional auxiliary potable water tanks installed in the centre
  wingbox, which increases capacity from the standard 1,700 litres
  (450USgal) capacity in six tanks to 2,270 litres - ie around 2.3t.

That's assuming that the 570 litre increase is entirely allocated to the showers, which may not be literally true.

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/3.0/


text:
Is there a tool to plot locations within X nm of a position?
I'm looking for a tool to allow me to see what is within X nms or X hrs of my base airport. Is there such a thing?  I remember a small airport I flew to once had a large map with a string attached to a pin located at the airports location on the map.  There were concentric rings from the location stating 100/200/300....nm. I'm basically looking for something like that such that I could explore and look for locations that are off my normal radar of places I would typically visit.  I typically use landings.com for baseline flight planning but you need an origin and destination. It doesn't look like it allows what I'm asking for.
I'd even be happy if there was a hack for google maps etc. to do what I'm asking.

Google maps already shows a scale on it. I would think using a ruler on the screen would give you at least the same level of accuracy as the piece of string on the wall map.

http://ourairports.com/ has a "closest airports" in the airport details tab that lists other airports, ordered by distance from the selected one.

Requests for specific tools are usually off-topic here but as it happens I was looking for something to do this a few days ago and found this

At least a couple of tools exist to search for airports beyond a certain distance from your departure point. You didn’t specify, so I will use mine: KHUA.
Using gcmap.com, search for near:KHUA beyond:50nm within:70nm to get a list of airports in the specified range.
To plot some of them on a map, place a few of those in a comma-separated list, e.g., KHUA,KGAD,KBHM,KSYI,KBNA,KAYX,M22,TN50,KJFX,KMRC,KAPT,KPYP,1M4,M22, and select the Map tool. Plot range rings with one or more lines in the Ranges box under Map Controls. I used

50nm@KHUA
  70nm@KHUA

Click the Draw Map button to update your map.
The final result will resemble the image below.

Google Earth probably has tools to do what you are looking for.  There's a lot of flexibility in that program to create overlays.  It can sometime take some knowledge of programming to do the more complex stuff but it is a very powerful program.

Yeah, I'm a programmer by trade and it dawned on me to use the google maps api.  I imagine I could use that but I'm really am curious of airports within X nm.  Just a tool to use to itch the scratch of "where can I go for a $100 hamburger."

"probably" is not an answer

gcmap.com allows drawing of range rings around airports. I think it's more geared up around longer range travel rather than the $100 burger, though.

all_licenses: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/3.0/


text:
On which axis do we measure angle of attack and airspeed?
The lift value depends on the relative airspeed of the plane. That's what every website says without anymore explainations.
But as we are talking about lift, are we talking about the relative speed ONLY on the axis of the chord line of the airfoil ? Or the relative speed, not related to any particular axis ?
Now about angle of attack (AOA ):
Is the AOA measured on a specific axis ? Or is it the absolue angle between the airspeed Vector and the chord Line ?
Or with other words : does AOA = 20° when the plane is on a 20° side slip ?? That's seems wrong to me but if we relate to the words of wikipedia for example thats what is being said.

Airspeed is always the total magnitude of the free-stream incident on the wing/airplane. In zero sideslip, angle of attack is exactly the angle between free-stream and body x-axis (could be chord for an isolated wing). In non-zero sideslip, it's nuanced; see below.
By industry standard (Ref. Etkins, Dynamics of Flight; Stevens, Aircraft Control and Simulation), the angle of attack ($\alpha$) and the angle of sideslip ($\beta$) are defined as Euler rotation from the coordinate axis attached to the free-stream such that the speed vector is $\begin{bmatrix}V_a & 0 & 0\end{bmatrix}^T$, where $V_a$ is the airspeed magnitude, to the body frame (where x-axis aligns with the chord):
$$\begin{bmatrix}u_a \\ v_a \\ w_a\end{bmatrix} = \begin{bmatrix}\cos\alpha\cos\beta & -\cos\alpha\sin\beta & -\sin\alpha \\
\sin\beta & \cos\beta & 0 \\
\sin\alpha\cos\beta & -\sin\alpha\sin\beta & \cos\alpha
\end{bmatrix}\begin{bmatrix}V_a \\ 0 \\ 0\end{bmatrix}$$
where $u_a$, $v_a$, $w_a$ are the incident speeds in the body frame.
Simplify, and we have:
$$\alpha = \tan^{-1}\frac{w_a}{u_a}$$
$$\beta = \sin^{-1}\frac{v_a}{V_a}$$

(Image Ref. Etkins, Dynamics of Flight)
Note that when sideslip is small (whereby $\cos{\beta}\approx1$), we can reduce the above to:
$$\alpha \approx \sin^{-1}\frac{w_a}{V_a}$$
Therefore, taking angle of attack as the projected angle between chord and free-stream is pretty darn good.

That's awesome ! Thank you very much.
Curious that all the websites are went to did not talk about that.
I understood, thank you very much.

@Anselme See the updated last paragraph. This clears up why most people don't go to the nuance.

Yep, I just saw it.
I am running a flight simulation I made and I was computing the lift while always considering the sideslip as 0.
But that's completely wrong at sometimes, performing dynamic stalls for example.
Thanks

Sorry, I was a bit to confident about your answer.
But something still doesnt make sense to me.
Let's take an extreme case where the plane is 90° from the relative airspeed.
Then w is 0 and the angle of attack (alpha) will still be 0, multiplied by the relative velocity squared, this gives us a prettygood amount of lift,as if it was flying forward.
But as no airflow is going in the chord direction NO LIFT is generated.
So our model is broken. Do we need to take the velocity parallel to the wind chord ?

@Anselme You're saying there's a 90deg sideslip? Put it to a wind tunnel and you'll see how much lift there is (in CL). Very small!

I am using this curve to get the CL from the AOA : https://en.wikipedia.org/wiki/Angle_of_attack#/media/File:Lift_curve.svg
I know there must be 0 lift with 90° sideslip. But using the AOA given by your formula and the fact we must use the "total magnitude of the free airstream" we get the same lift value as if the plane was going forward.
So the question, I am asking again : in those equations and curves, HOW is aoa measured ? When the sideslip is 90° I should compute my lift with ONLY the AOA value projected on the xz plane, otherwise it does not makes sense...

I'm in a simulation so I need to COMPUTE the lift given my wing orientation and the relative airflow.
If I measure the AOA as you said, and if I use the lift-to-aoa curve I found, it's total wrong, as I just explained why.
I think I will stay on measuring the projected AOA and the projected airspeed along the body. Im sorry maybe I'm not explaining well but I think we are not understanding each other.

@Anselme First, that's just a sample curve. Your wingbody will be definitely different. Second, that curve is for small sideslip value for that sample wing. At extreme sideslip, you will most definitely have considerably different characteristics. Third, even Level D  simulators for high AOA fighters are only good up to around 30 deg sideslip and 40-50 AOA. The aerodynamic data are carefully gathered from wind tunnel and flight testing.

ok thank you for the informations. As it is a simulation of course I am not trying to make the next airforce training software. I must approximate things and thus using this curve has given me really cool flying results at low speeds, I managed to reproduce the same flight characteristics of the sopwith Camel. Same stall speed, same cruise speed, all of that without hardcoding anything. So what I am doing is far of being completely out of reality.

@Anselme I suggest you take a look at this video series: https://www.youtube.com/watch?v=EeGdQA76SVg&list=PL_onPhFCkVQgZAwQ6arEynypDUWfZOGXf&index=71.

Angle of attack is always measured as the angle between the chord line and the relative wind.  Different aircraft orientations will cause differences in angle of attack between the two or more wings on an airplane or the rotor on a helicopter.  For example, stalling an airplane while in uncoordinated flight can lead to a spin as the inner wing achieves a greater angle of attack than the outer wing.

Thank you for your answer.
"Angle of attack is always measured as the angle between the chord line and the relative wind."
So that means a plane yawing 20° from the flight path while being straight level and maintaining sufficient speed will be stalling ?? That does not make any sense to me.

It might be stalling, but it might not.  It depends on the AoA.  The yaw angle is not the same as AoA.  (which has already been defined)

It has been defined  by : "Angle of attack is always measured as the angle between the chord line and the relative wind".
So if the relative wind comes from a 30° yaw angle, then AOA is the SAME as yaw angle.
Or maybe the definiton of the AOA works only with 2D vectors and not 3D one ?

@Anselme, Ok, sorry...  I see where your confusion is now, and perhaps I wasn't clear. AoA is not a measurement of spanwise flow, it is a measurement of the angle of flow that is parallel to the chord.  In other words, you would see this angle from a side view, but not a planform view.  (Reference figures in other answer)  Does this make sense?

Nice, now all is clear ! Thanks


text:
Thrust difference between GE90-115B and RR Trent XWB-97 vs. related aircraft MTOW difference?
Looking at Boeing 777-300ER and Airbus A350-1000 engines at Wikipedia:

Aircraft
B777-300ER
A350-1000
difference

Type certificate
No. EASA.IM.A.003
No. EASA.A.151

Engine model
General Electric GE90 115B
Rolls-Royce RR Trent XWB-97

Engine parameters
2-shaft  Fan Dia=3.3m  4LP-9HP compressor  2HP-6LP Turbine
3-shaft  Fan Dia=3.0m  8IP-6HP compressor  1HP-2IP-6LP Turbine

Engine datasheet
No. IM.E.002
No. EASA E.111

MTOM
351 534 kg
322 000 kg
-8.40%

MLW
251 290 kg
236 000 kg
-6.08%

take-off thrust
513.95 kN
431.5 kN
-16.04%

TO thrust / MTOM
1.46 m/s2
1.34 m/s2
-8.34%

TO thrust / MLW
2.05 m/s2
1.82m/s2
-10.60%

The A350 is 8.4% lighter at MTOW but has a substantially lower  take-off thrust (-16%):

How is reduction of thrust feasible in larger MTOW aircraft whilst not compromising on go-around climb gradient and other parameters related to application of take-off Thrust?

Why are the thrust reduced in newer aircraft models as compared to older models ?

You're not comparing the same thrust number. The XWB-97 is 97,000 lb takeoff and 83,100 lb max continuous. The GE90-115B is 115,540 lb takeoff.

I fixed the thrust value as suggested by @user71659. The relative difference in thrust is still larger than in MTOW, so the question remains valid.

@Bianfable we were working on this at the same time, I largely overwrote your edits with mine. Our percentage differed, because I took the 777 as reference, you took the A350. The result is that my percentage are somewhat smaller.

First off, for the same number of engines, the missed approach criteria (thrust-to-weight ratio) as derived from the regulations depend on the lift-to-drag ratio, which in turn depends on the wetted area (smaller for the 1000 due to its smaller fuselage, which cancels out the difference in aspect ratio more or less). Also, the missed approach climb segment is the least constraining element (see diagram below); and that's not taking into account the advancements in flap design (see this Q&A and this Q&A).

Via https://www.fzt.haw-hamburg.de/pers/Scholz/HOOU/AircraftDesign_5_PreliminarySizing.pdf

(Also see the pdf for the equations.)
Second, the 1000 received a trailing edge modification increasing the wing area (reason in this Q&A); this reduces the wing loading compared the 300ER, which works for the take off performance.
The big question is how does it achieve the same cruise performance, e.g. the A330 is slower than the 777, but that's not the case here.
Here being built lighter (OEW by 12 tonnes) means cruising higher sooner with the same payload, and the newer engines run for longer on the same fuel.


text:
What does this symbol mean?
Does anybody know what the icon inside the circle mean ?

Found at aviationweather.gov

Where does this image appear?

Looks like Duffy Duck.

Perhaps it means: it's bloody cold, bring a balaclava.

https://www.aviationweather.gov/metar it is where i found the image

It seems to be the symbol "M" for "missing cloud information". Note that CWIJ has a circle for cloud coverage that is slightly bigger than the standard circle size used for most other airports.
Southeast of CWIJ, there is CWIC which has the symbol M as well, but there the edge of the circle coincides with the lower part of the symbol shown in the CWIJ circle.

Another example can be found with CXDK (normal size circle) and CXLL (big circle size)

There is another station towards the east (CYBK) that has a bigger circle as well, and it has a 6/8 cloud coverage symbol that does not fully fill the circle. For comparison, PAUM has a standard circle size with the same 6/8 cloud coverage symbol filling all the way to the circle's edge.

This leads me to believe that the software behind aviationweather.gov has a symbol library which includes cloud coverage symbols designed for a certain standard circle size. Some airport are represent by a circle which is bigger than the standard, and this leads to the strange representation of the symbol 'M' seen at CWIJ.


text:
Can someone identify the Make and Model of airplane that this fuselage belonged to?
This gutted fuselage remnant was photographed by my mother at Whaler's Bay on Deception Island in Antarctica in 1994.  Deception Island is directly south of the Falkland Islands in the narrow area between South America and Antarctica.  Where the wing attached to the fuselage there is grey hand-printed writing that appears to be: 3G9SAY.  Below the windows, also in grey printing are three lines of faded print.  The first line appears to be something like: ESTACION JERASSIEN.  The second line appears to be: BARDA HARE. And the third line appears to be: AGRVFACIAL PIORK.  But I stress that I'm doing a lot of guessing at these letters so interpret them loosely.  Thank you for your assistance in identifying this aircraft.

That looks like the remains of a De Havilland DHC-3 Otter
It used to wear the registration VP-FAK.

British Antarctic Survey (BAS) and the de Havilland Aircraft Heritage Centre at Salisbury Hall, London Colney have agreed on a long term loan for BAS DHC-3 Otter VP-FAK.  This historic artefact was recovered from Deception Island, Antarctica in April 2004 where it had lain for nearly 40 years since the aircraft was grounded due to structural problems.
De Havilland Canada Otter VP-FAK c/n 294 made its maiden flight in
Canada on 17 October, 1959.  It was shipped to Deception Island
arriving on 26 January 1960 before assembly and flying on 3 February.
The aircraft was flown by aircrew seconded from the RAF to BAS when it
carried the identity 294 with RAF roundels.  Flying conditions in the
Antarctic are very demanding and the aircraft was damaged a number of
times, the last time at Adelaide, making its last flight from there to
Deception Island on 7 March 1967.  Following an inspection it was
grounded due to structural problems, having flown 981.30 hours and
made 853 landings.  The aircraft was stored outside at Deception
Island in a dismantled state until recovery to Rothera ready for
shipping to Britain, where it arrived at Grimsby on 8 May 2005.

More information here

Salisbury Hall is a few miles from my house, and is now the de-Haviland aircraft museum. One of my favourite places to visit! I hope they survive with no visitors for over a year now.

They were replaced with Twin Otters which were far more suitable, having PT-6s in place of the R-1340, and are still in production today https://www.vikingair.com/twin-otter-versatility/twin-otter-stories.  The R-1340  version used in the Otter was geared, with the engine turning faster than the direct drive version (as used on the T-6 for ex) and made more HP, but they had reliability problems in later years and were known for blowing jugs.

@DeltaLima - You nailed it. Thank you!  That is exactly the very plane my mom photographed 10 years before it was recovered. And thank you for finding the story about its recovery.  Restoring it "as far as possible" appears to be a monumental task.  I wish my mother was still with us and knew about this.


text:
Do aerodynamic forces and moments change aircraft pitch and yaw in the same way?
Several questions on the Aviation SE site have dealt with the question: can the rudder alone turn the aircraft:

This one, which was marked a duplicate of
this one, which was itself marked as a duplicate of
this question, with a skilful and detailed answer.

So we know in triplicate that the rudder alone can turn an aircraft. Not very comfortably due to the side forces, wrong way lean, different airspeeds on inside & outside wing etc, that is why the normal way to turn is to bank.
However, the following has been posted in the comments (partial quotes only due to length):

Yaw does not cause aircraft turn. It only causes yaw. Yaw is not turn.
Lift, pointed in a direction other than perpendicular to the horizon, is what creates turn. Nothing else.
With no other yaw force on the aircraft, if you have right rudder, that does create a leftwards force, but it also creates a right yaw (sideslip) which itself creates a rightwards force that opposes the leftwards force from the rudder.
It works in exactly the same way as it does in pitch. The elevator pulls the tail down and, because it's behind the CG, creates a nose up pitching moment (torque). Lift on the wings lifts the aircraft up, and because it's also (generally) behind the CG it produces a Nose down pitching moment. Because the moment arm of the elevator is so much longer the torques balance, but the Up force from wings is much larger than the down force from the elevator and the aircraft is able to fly. The force from the rudder, and the force from the sideslip angle of the fuselage act in the same way.
The nose of the aircraft does not "turn" away from the "direction the pilot ... " it only "yaws" away, and it only yaws away until the sideslip angle reaches the point where equilibrium occurs.

The gist of all this is that the aircraft would behave in yaw in the same way as in pitch: rudder deflection only causes an angle of sideslip, not a continuous turn in heading. That would conflict with the earlier questions posted above.
So the question is: does yaw really behave exactly like pitch? Does deflecting the rudder only cause a greater angle of sideslip but no flight path change?

What are the assumptions required for the answer? are we applying only rudder and are we leaving the bank angle free to increase or are we applying aileron to keep the wings level? are we increasing thrust or are we leaving the aircraft free to decelerate due to the increase in drag?

@Federico good questions that will lead to a good answer I reckon.

Should we expect that changing the aircraft's vector in a direction parallel to the lift vector (i.e. pitch) will work the same as changing it in a direction perpendicular to that vector (i.e. yaw)?

No, I won't answer before knowing what are the assumptions required.

@jjack that's not sufficient and you're not the OP

@Koyovis, Thank you for posting this. I appreciate your continued interest in delving into the concept at a deeper level.

You could also take into consideration the secondary effect of yaw, which is roll. As the aircraft yaws one wing moves forward in the airflow while the other moves back. This increases the amount of lift generated by each with the wing moving forward creating more lift and the trailing wing creating less. The aircraft therefore, will roll in the direction on yaw. This can be countered by applying opposite aileron.

Yes, however since the rudder sticks out above the fuselage, deflecting rudder creates an immediate rolling moment to outboard, only later compensated for by the effect you describe.

Assuming that the center of pressure for the rudder airfoil lies above the flight path of the aircraft CG. If the center of pressure happens to be below the extension of the flight path from the CG, then the aircraft will roll right from right rudder. This can be the case because of unusual aircraft design, or from very high AOA. Also, in swept wing aircraft, yaw produces roll due to decreasing the sweep angle on the wing moving forward, and increasing the sweep angle on the opposite wing.

Finally, in high performance aircraft, roll at high AOA itself produces a pitch moment, increasing AOA. This effect, now called Inertial roll coupling, caused loss of control and the loss of an F-16 in the mid 80s (I believe). It comes because the aircraft is rolling about its flight path, not its fuselage, and its kinda like mounting a barbell on a steel rod that is offset from the bar by some angle, and then spinning it on the steel rod. The two ends of the barbell will describe circles around the steel bar rotational axis, and exert a centrifugal force that pulls them further away.

Of course will yaw also change direction if we define this as a change in the flight path. But it does so much less efficiently than banking.
Yaw creates a side force on the fuselage and fins which accelerates the aircraft sideways. This does change the resulting flight path, but the amount of side force is small due to the low aspect ratio of the fuselage. The lift-to-drag ratio of the fuselage is poor, so another change to the aircraft's vector is a deceleration if the increased drag is not compensated by more thrust.
Banking also creates a side force (when seen in the geocentric reference system), but now the wing is responsible for that force. Its lift-to-drag ratio is much better than that of the fuselage, therefore, the amount of side force is much higher and less drag is created. By first banking and then pulling more than 1g, the pilot changes the flight path much more effectively while maintaining altitude.
So the answer is yes, yaw behaves the same way as pitch. Only the wing and elevator are replaced by the fuselage and fins, with all changes to the magnitude of the forces this causes. The only difference is that pitch is needed to adjust lift, and changing the pitch attitude will change the speed of the aircraft or the load factor. Flying in a sideslip with no adjustment for the side force by a corresponding bank angle will continuously accelerate the aircraft sideways and will result in a uncoordinated turn. Now the sideways load factor (which is zero in coordinated flight) will be nonzero while in the longitudinal motion the normal size of the load factor is one (and be different from one when pitch is changed).
EDIT:
@TomMcW has contributed a practical example in the comments. Consider a crosswind landing with a glider or motor glider where crabbing is your only option to fly a straight approach over ground. Right before touchdown you should then step on the rudder to align the aircraft with the runway so the tires can touch down without moving sideways. Now consider that you stepped on the rudder too early and the aircraft floats along the runway with a sideslip angle. You will drift leewards, right? That is exactly the change in flight path I am talking about.
In crabbed flight the aircraft flies without sideslip. The fuselage with its forward center of pressure position destabilises the aircraft in yaw and the vertical tail adds the required stability. Both create no side force in crabbed flight. Now you want to align the fuselage with the runway and step on the rudder: The tail swings the aircraft around into a sideslip until the fuselage points into the desired direction. Now opposite rudder must be applied briefly to stop the yawing motion and then returned to a position between neutral and the initial deflection in order to trim the new sideslip. Note that this works exactly in the same way as the elevator when a new angle of attack is trimmed!
In the sideslip condition both the fuselage and the vertical tail will create a side force in the same direction. The side force of the fuselage is higher because its center of pressure is closer to the center of gravity than that of the tail, and in order to reach an equilibrium, both must point to the same side. This combined side force accelerates the aircraft sideways such that a speed component is added which reduces the sideslip condition. Since the aircraft is trimmed for a specific sideslip, the changing balance of moments with a change in sideslip will yaw the aircraft further so that the trimmed sideslip angle is restored.
Why is that? Remember that the rudder is deflected. This creates a camber in the vertical tail which moves its zero-sideforce angle of sideslip away from the sideslip angle of zero to a negative angle (for example, right rudder deflection will shift the zero-sideforce sideslip angle on the tail to a left sideslip value). Any change in sideslip will, therefore, bring a relatively larger change in side force at the tail which changes the balance of yawing moments such that the old sideslip is restored. Note again how similar this is to static longitudinal stability.
This means that the aircraft must maintain a slow yawing motion in order to keep the sideslip constant. The side force causes a reduction in sideslip and the yawing motion is a result of the sideslip-maintaining tendency of the vertical tail.
And, no, yaw is not a moment. Please let's all use an agreed version of English.

Does deflecting the rudder only cause a greater angle of sideslip but no flight path change?

@Koyovis: No, in addition to yaw the flight path does change, too.

@Koyovis In a crosswind landing you can use either bank or yaw to compensate. If yaw didn't affect flight path you couldn't do a crabbed landing.

@TomMcW: This is a little different. In a crabbed landing you only fly with a sideslip right before touchdown (if performed right). You want to keep the sideslip part of the landing as short as possible precisely because the side force involved will accelerate the aircraft sideways and makes it leave the runway to the leeward side. But that is precisely what my answer is about, so your example is actually very helpful.

It's a strangely worded question.

@TomMcW I know, it's from this bit It works in exactly the same way as it does in pitch

The core of the snippet extracted from my post on another question is the distinction between torque (Yaw is a torque), and force (Lift is a force).  To change direction requires lateral acceleration (ft/sec2) which can only be achieved by the application of a force. Yaw is not a force - It is a torque, or a moment, which [directly], can only produce rotational acceleration. In an aircraft this produces a sideslip, which, as it increases, causes a reduction in the yaw moment and an increase in the opposing sideslip moment, until equilibrium is reached.

The comment from @TomMcW illustrates the confusion involved in this concept. Once established at the equilibrium sideslip angle (where the yaw moment from the lift generated by the rudder is equal to the opposite yaw moment from the Lift from the sideslip angle, the aircraft would in fact turn (unless you establish a bank to correct). But it would be turning as a result of the difference between the two opposing lift forces, not from the yaw moment of the rudder alone.

Think about it. Rudder creates lateral Lift (right rudder creates LEFT Lift. This lift force to the left, at the tail, creates right (clockwise from above) moment about the yaw axis (vertical) at the aircraft CG, with a moment dependent on the distance between the CG and the rudder. The aircraft begins to yaw to the right. As it does, the angle of attack on the rudder decreases, reducing the Lift force to the left. As the right sideslip increases, the fuselage lift force to the right increases. This right force creates a counterclockwise moment about yaw axis.

This continues until the decreasing clockwise moment from the rudder is equal to the increasing counterclockwise moment from the fuselage sideslip force. At this point the yaw or sideslip angle stops changing. The aircraft is in equilibrium (as far as yaw or sideslip angle is concerned.). However, to get to this equilibrium, because the rudder has a longer moment arm than the center of pressure of the fuselage, requires a much larger fuselage force than the rudder force. So the sum of the two forces, is still to the left. This total force is what is turning the aircraft.

@CharlesBretana: Yaw is a state or a movement. I link to the definition of the noun in the Oxford dictionary as proof.  If you redefine it as a moment, feel free to add your own answer. Until then I will prefer to use the word as it is defined in the standard reference for proper English.

The physics doesn't really care how the dictionary defines it. A body in flight responds to forces, and moments created by those forces. Ignoring the moments because of how you understand something in a the dictionary would not even be wrong.  The word "Yaw" is used in multiple contexts, and in many of these contexts means things that are entirely appropriate in that specific context, but are totally inconsistent from the meaning  intended in other contexts. I cannot imagine that you do not understand that.

@CharlesBretana: Downvote me as much as you like. You should try to argue convincingly rather than show the meanness of your character.

OMG, Peter, "try to argue convincingly" ??? What do you think I am doing? this topic is an important one, and I have invested several hours in detailed answers and comments to other answers attempting to communicate this concept. If you see only an attempt to be mean-spirited, well, All I can say is I am sorry you feel that way. Perhaps you should ignore this thread and go elsewhere.   and oh, btw, the definition in the link you provided can be interpreted as a sideslip angle, or as an action to create a yaw moment, or as the moment or as a force. All of these would satisfy the definition

@CharlesBretana: Put your behind into an aircraft and try for yourself. This should be an enlightening experience. And try to use proper English.

@Peter, I have 3000+ hours of time "in an aircraft". And I have a master's degree in Aeronautical Engineering.  Not that who I am or what my experience or education might be can change the validity of anything I have been trying to communicate. To maintain that (positively or negatively) would be arguing "ad Hominum".

@Peter, Look, I respect everyone's opinion. And I am happy to discus the substance of any of these arguments if you wish to. I downvoted your answer because I believe it is wrong, not because I am trying to embarrass you or hurt your feelings. If you took it that way I am sorry.

@Peter, One more attempt... here's another idea to think about. If as you maintain, right rudder, by itself, causes the aircraft to turn right, then how do you reconcile this with the fact that the force produced by the right rudder on the aircraft is to push the aircraft to the LEFT? Obviously, it must be to the left, as it torques (pushes) the tail to the left (and the nose to the right).  The answer is that it does push the aircraft to the left, not to the right, but this effect is negated and counteracted by the much larger rightwards force from the sideslip angle on the fuselage.

Let us continue this discussion in chat.

The flight path of the aircraft CoG is defined relative to earth axes. In the six degrees of freedom of a rigid body, the three angular DoFs are defined as:

Pitch is the nose up/down angle relative to the gravity field of the earth.
Roll is the wingtip up/down angle relative to the gravity field of the earth. The angle relative to gravity is also referred to as the bank angle.
Yaw is the angle relative to a suitable earth reference, usually magnetic north or geographical north. Note that yaw is defined as an angle with reference to earth field of gravity, writing it with a capital does not re-define it as a torque about the aircraft Z-axis.

There is additional information here. Aircraft pitch, roll and yaw are defined with reference to earth field of gravity, while aerodynamic forces use the aircraft axes, described in more detail below. Aircraft axes are defined relative to the free airstream - to avoid confusion, nose-up angle relative to free airstream is defined as Angle of Attack, and nose sideways angle as Angle of Sideslip. Confusingly, aircraft pitch, roll and yaw is sometimes used relative to free stream, which is only valid if the aircraft flies at constant altitude in the direction chosen for yaw.
The aircraft axes and sign definitions used for aerodynamic force considerations are defined as follows:

Aircraft motion and forces about the angle of attack axis (X-axis) is also referred to as symmetrical flight in aircraft stability and control: equilibrium of forces and moments in the plane of symmetry of the aircraft. For a-symmetrical flight, we look at forces, moments and deflections around the Z- and the X-axis, and forces in direction of Y-axis.
A rigid body has six degrees of freedom: three linear displacements, and three angular ones. Stability and Control of aircraft generally divides aircraft behaviour into:

Symmetrical behaviour: forces, moments and displacements in the aircraft field of symmetry of the aircraft (nose up/down). Note that the gravity vector is then broken into components relative to aircraft axes.
A-symmetrical behaviour: forces, moments and displacements not in the aircraft field of symmetry.

The three equations that determine the state of stationary, a-symmetrical flight are the forces in Y-direction, and the torques about the X-axis and the Z-axis. Within these three equations, there are five variables:

rudder deflection;
aileron deflection;
sideslip angle;
roll angle;
yaw angular velocity.

A resulting angular velocity $r$ can therefore be the result of an infinite number of combinations of the remaining four variables. Only if one of the variables is fixed, is the resulting $r$ a function of the remaining three variables. For instance keep the ailerons at zero, and a rudder deflection results in a sideslip angle, a bank angle, and a nose sideways angular velocity. Different combinations for different aircraft. A much better option is of course to choose sideslip angle zero: a combination of ailerons, roll and rudder then results in a co-ordinated turn.
Image source
Aircraft heading change is the result of a sideways force relative to the velocity vector and to the earth field of gravity: a force in this direction acts as a centripetal force. There is an infinitely large combination of aircraft states that can cause heading change and turn the aircraft.
Deflection of rudder only is one of them: it is the back-up mechanical mode of the A-320, and is the way that Anthony Fokker controlled his flying birds nest, the "Spin", which had no ailerons. This way of turning is uncomfortable due to rolling the wrong way when the rudder sticks out on top, creating the rolling moment; and due to cross-effects with increasing sideslip drag and a-symmetrical lift. Pilots are taught to turn the aircraft using the ailerons, and only use the rudder to keep the nose in the wind, for a very good reason!
Does aircraft yaw behave like aircraft pitch?

Yes of course, in the way that it responds to moments and forces around the CoG. Basic physics.
No, in the way that there are more degrees of freedom for the aircraft to change heading. In pitch, elevator deflection changes AoA changes wing lift: one degree of freedom. in yaw, either rudder deflection or aileron deflection creates the combination of yaw and/or bank angle resulting in the centripetal force that changes flight path.

So, are you concluding that yaw does or does not behave the same way as pitch? Basically, if you boiled this answer down to yes or no, which would it be?

@Koyovis, +1 for first sentence in your last paragraph - spot on correct.  TomMcW, As in most things technical, it depends on the context. In this context, "the way it affects aircraft trim about the corresponding axis of rotation", the answer is yes, it behaves exactly the same as pitch.  If you want to include everything including which axis of rotation it affects, then obviously the answer would be no. How should he "boil" that down?

@Koyovis, for second sentence in last paragraph, "No, in the way that there are more degrees of freedom for the aircraft change heading.", How are there more degrees of freedom? In pitch, Once the aircraft pitch AOA is in equilibrium (and AOA is static) the aircraft will either maintain pitch flight path (in level flight or constant climb or dive angle), or it will increase or decrease flight path pitch angle. These latter two conditions are both "turns" in the vertical.

First of all, by Yaw, I mean the torque or moment created by the lift produced by the vertical stabilizer and rudder when at a sideslip angle, acting on the aircraft through a moment arm between the CG and the rudder.
This Yaw, itself, exclusive of analyzing the total sum of all other aerodynamic forces on the total surface of the aircraft, does NOT cause the aircraft heading to continuously change.
F=ma !!!!
Unless the total lateral force (parallel with the wings) is non- zero, the aircraft will remain on a constant heading. Yaw, (by definition) is nothing more than the condition that the aircraft Heading is not aligned with the relative wind. PERIOD.
Depressing the rudder, does cause a Yaw. But it also causes Lateral Lift to the side.  It is this Lift which can potentially cause the aircraft to turn.  But it will ONLY cause a turn if the sum of all other lateral Lift is insufficient to balance out and compensate for the Lift created by the rudder deflection. The sideslip generated by the rudder (THIS IS THE YAW) also generates Lift, and it is in the opposite direction from the Lift generate by the rudder Lift. Which direction the aircraft turns in is determined by the total Lateral Lift produced by not just the rudder, but by all aircraft surfaces, including the side of the Fuselage as a result of the sideslip.
The point is that it is not the Yaw which causes the turn, as Yaw is a torque. It is the Lift. Lift Is a force
Yaw is torque, and can only produce rotational acceleration, which can only change attitude, and the equilibrium sideslip angle. Absent a non-zero total lateral force, it cannot change direction of motion. It will just change the angle of the fuselage to the relative wind, (sideslip). As the sideslip increases, the torque from the rudder deflection decreases, and the opposing torque frm the sideslip increases, until they reach equilibrium. At that point, the sideslip angle stops increasing.
IF at this point of equilibrium, the total lateral (sideways) force is non-zero, then the aircraft will turn.
As a thought experiment, imagine a side thruster on the nose of the aircraft pointing to the left, that puts out 100 pounds of thrust, let's say, 5 feet forward of the aircraft CG. This would produce the exact same right Yaw as a rightwards rudder deflection at the tail, that produced 50 pounds of leftwards force on the tail, 10 feet behind the CG. Clearly, the aircraft is not going to turn in the same direction at the same rate of turn in these two scenarios. Why Not? you might say - the yaw is the same!  Both are producing an identical amount of Yaw (500 ft-lbs) in the same direction (clockwise)! But obviously, they do not.  This is because, absent consideration of the forces produced by the fuselage due to the sideslip, the rocket thruster is pushing the aircraft to the right, and it will turn right, the rudder is pushing the aircraft to the left, and, (Absent consideration of sideslip forces),  it would turn left.
It is difficult to understand this because any aircraft has a fuselage, with significant sideslip forces, and these distort the effect of the issue, but if you imagine an aerodynamic body that consists of a flat plate and a rudder, so that there is no sideslip force, then imagine what would happen if you deflect the rudder. Why, the entire body would just spin around the yaw axis until the rudder is once again streamlined in the relative wind, and there would be no turn created at all.

Yes, but the rotation (the angle between fuselage and relative wind),  is the result of the moment.  The moment, and the force that produces that moment are the two abstractions we are discussing. When I use the term Yaw I am referring to the moment, not the sideslip that results from it. And you need to be careful about using the term rotation. In this context it does not mean continuous rotation, it is just the static angle between the two vectors.

You are empatically stating that deflecting the rudder alone does not change the aircraft heading, is that correct?

@Koyovis, No, What I am emphatically stating is that the yaw, or yaw moment from the rudder deflection does not turn the aircraft. Lift generated by the vertical stabilizer and rudder, creates a yaw moment (which causes sideslip), and a horizontal force opposite the rudder. This horizontal force can turn the aircraft, but it will turn the aircraft only if the sum of all other forces (from fuselage sideslip, asymmetric thrust, etc.) is non-zero and the turn generated will be in the direction of the total lateral force, which may or may not be in the same direction as the rudder force.

@Koyovis, If you imagine a rudder, by itself, moving through an air mass. Now apply a force (How doesn't matter) that twists the rudder by some angle to the right. What would happen? would the rudder start to turn continuously? of course not. Now put the rudder on a stick, which is of minimal thickness, but measurable mass, (so that the CG is forward of the "rudder", and repeat. What will happen? The entire body will twist laterally until the rudder is again aligned with the relative wind, and then it will remain in that stable position.

But if you put another fixed vertical airfoil surface forward of the rudder, also behind the CG, and repeat, something entirely different will happen. Exactly analogous to the balance of moments which occurs in the pitch axis from the wings, and elevator of an aircraft, this "arrow" will yaw to the side, reducing the rudder angle of attack (and it's moment) and increasing the angle of attack of the vertical airfoil in front, until the opposing moments of the two airfoils are in balance. No further change in sideslip angle will occur.

But if leftwards force from the forward airfoil (with a shorter moment) is greater than the rightwards force from the udder (with a longer moment) the body will establish and maintain a continuous change in lateral heading (rate of turn) to the left.

Another analogy... Roll an aircraft into a 90 degree left bank, and pull back on the stick/yoke. The aircraft will turn left. Would you say that it is the elevator nose up Pitching moment that is turning th aircraft? No, of course not. It is the lift on the wings that is turning the aircraft. All the elevator did was change the trim about the lateral (pitch) axis in such a way as to increase the AOA on the wings, producing more wing lift. It is the wing lift that turns the aircraft. The elevator lift is actually impeding the turn rate.

The rudder creates a side force and a torque around the COG. The vertical tail also creates a side force and a moment. So does the Y-component of gravity when banking. The total resulting side force in earth axes provides a centripetal force that turns aircraft heading. Aircraft axes are not earth axes, and you should take care in not mixing up effects from one reference frame into another.

@Koyovis, I am not mixing them up. Are you saying that I am? If so, please quote my statement that confuses them.  By the way,when the rudder is deflected, say, to the right,  the rudder and the vertical tail, together, form a airfoil. The deflected rudder moves the Mean Aerodynamic Chord (MAC) of this airfoil to point to the left of the fuselage center line, creating a non-zero AOA,. which (initially at least), creates an aerodynamic force towards the left. This aerodynamic force will decrease as the aircraft yaws to the right, decreasing the AOA.

In reality of course, every square millimeter of both sides of the rudder and the vertical tail is experiencing the pressure of the airflow across it, but It would be unnecessarily complex and pointless to attempt to deal with the force created by each square millimeter separately (although I have written Finite Analysis software routines which approximate Navier-Stokes to do just that). It is equally pointless to analyze lift force from the rudder separately from the force created by the vertical tail, although if you really did that you would still end up with the same result.

And gravity cannot turn the aircraft. I apologize if this sounds pedantic and condescending, but, gravity is not an Aerodynamic force. Second, it always points down, so how can it ever cause a change in aircraft flight path? Bur even if we postulated a Gravity force that pulls to the side, (imagine a giant electromagnet that is pulling the aircraft sideways), this again, is not an aerodynamic force, and has no place in this argument. No matter how much such a force might cause the aircraft to turn, the turn is not being caused by an aerodynamic force, it would be caused by the magnet.

@Koyovis. Your first sentence above I agree with completely "The rudder creates a side force and a torque around the COG", except that I might say that "The combined Rudder and Vertical stabilizer creates a side force and a torque around the COG." - Right rudder, side force to the left, and Torque about the CG clockwise (as from above). Do you agree with this? (Consider the initial instantaneous state after rudder is deflected but before aircraft begins to yaw nose right) BTW, would you like to continue this back and forth on the discussion forum?

@CharlesBretana no, I don't agree with that. The rudder creates a side force proportional to rudder deflection and to local angle of sideslip. The vertical tail creates a side force proportional to local angle of sideslip. Both forces are relative to the aircraft axes. Since both side forces are not generated in the CoG, they both create an additional torque about the CoG. Continuing this discussion has very little value for the rest of the community, since your contribution consists of a confusion of half-truths.

Every sentence in your last comment is wrong. The force is not proportional to rudder deflection, or to sideslip angle. It is proportional (dependent would be better word, since the relationship is not linear) to the AOA of the airfoil formed by the combined rudder and vertical stabilizer. The rest of your comments are similarly incorrect and inaccurate. But the more I read, the more I realize that you are correct in one thing. this conversation is pointless. You are unwilling, (or unable) to discuss this on substance and continue to avoid actual analysis. Good day to you sir.


text:
How do planes benefit from flying in formation?
Large flock of birds when migrating usually fly in an arrow formation, which helps the birds to save energy while flying the same distance as compared to a situation when the birds are not in a group.

What is the physics behind this?
What is the significance of the specific flying formation?
Can this be applied on airplanes (given the fact that anything analogous to engine exhaust is not present in birds)?

possible duplicate of Is the V flight formation being used for commercial purposes?

that question does not explain the physics behind the 'V' formation

@CGCampbell I am doing some research on this right now (online ofcourse) and turns out the physics behind the planes and the birds saving enery by flying in the V formation (which I called the arrow formation) is the same. So that makes the question On Topic. Again the question is not too broad as I am asking in reference to a particular phenomenon which has a very specific answer.

I reflect the same sentiment!

You do realize, of course, that you are still asking 3 questions here?

Energy saving
The wing creates lift, which is upward force on the wing. According to principle of action and reaction, there must be a downward force acting on the air. This force creates a downwash behind the wing. As the accelerated air interacts with the still air further away it turns to the sides and back up, creating a slight upwash outside of the wingtips.
Flying in this upwash adds a bit of lift on the next flying thing which in turn means it can fly at slightly lower angle of attack and have less induced drag. This recovers some energy from the wake vortex that would otherwise be dissipated as heat.
Birds
Migratory birds use the typical V formation to take advantage of this, each bird flying aft and to the side of the previous. Since the leader is not getting any advantage, the birds usually take turns in leading the flock.
Aircraft
I have however not heard of this being done with aircraft for energy purposes beyond experiments. Military aircraft usually use similar V formation, but for different reasons. They need to fly in group, because they need to provide mutual defence. And then the V formation is used during cruise to and from target area simply because in it the wingmen see the leader while remaining clear of their downwash and wake turbulence.

Really interesting, could you elaborate on this specific angle: I had the feeling that the first animal/object was doing some work for the benefit of the others (the upwash stream), but actually it seems the total quantity of work is decreased. How can that be? Thanks.

@mins: The leader is doing exactly the same amount of work that they would if they were alone. What happens is that the followers are able to recover some energy from the wake vortex that would otherwise be dissipated as heat.

"provide mutual defence" Lessons learnt during WWII would disagree with that. The RAF paid a heavy price to learn that flying in formation requires skill and concentration that could be better spent searching for the enemy.

@Aron: The formation is mainly used for flight to and from the target area where the pilots need to be aware of each other so they don't break up. In the actual fight the formation is broken and each plane manoeuvres on its own, the offensive/defensive roles only governing their choice of targets (speaking of fighters; bombers don't fly in formations much any more).

Does military formation flying have any more practical use than the close-order drill I had to do in boot camp?

@jamesqf: It is a standard method for staying in compact group relatively safely during cruise and it is the same skill needed for aerial refuelling and peace-time intercepts.

The part about the birds taking turns is super fascinating! +1

@aron - the RAF learned that the "Vic", a tight 3 ship formation V formation, didn't work well. They quickly learned that the looser "Finger 4" four-man (two pairs of wingmen), however, allowed a great degree of flexibility and ability to cover each other. The British 3 man formation worked well pre-WWII in lower speed aircraft, it just needed to be loosened up with faster aircraft, and 2 pairs made more sense at that time.

Canada Geese are famous for taking advantage of this phenomenon-- they use the wingtip vortices caused by the bird right in front of them, to decrease drag during flight.
You can see wikipedia for some information regarding "V" formation
and aviationweek for a relevant USAF experiment involving C17 aircraft.


text:
Are there any civilian powered-lift aircraft besides the AW609?
I was looking at the difference between rotorcraft and powered-lift and every example I saw was a military application (Osprey or Harrier or F35)
The FAA defines powered-lift:

Powered-lift means a heavier-than-air aircraft capable of vertical
  takeoff, vertical landing, and low speed flight that depends
  principally on engine-driven lift devices or engine thrust for lift
  during these flight regimes and on nonrotating airfoil(s) for lift
  during horizontal flight.

I was wondering if there were any small, personal powered-lift aircraft that one might get their private pilot license in the way people get a ASEL certificate in a 172.
I know there is the AW609, but that is targeted towards the business market with a very specific niche.

The Harrier has some private owners and could be considered a "small" powered lift aircraft. The issue I see though is that powered lift is somewhere between a helicopter and an airplane, and is probably not the best choice of aircraft for primary training.

I suppose some kinds of roadable aircraft aka 'flying car' designs would qualify under the powered lift category.  One example which nearly escaped the prototype stage was the Moeller SkyCar.

But beyond the Agusta AW609, I cannot think of any other powered lift category aircraft which are, or may be soon, available for sale to the general public.

The first Powered Lift pilot certificates were awarded to V-22 Osprey test pilots in 1997, I'm not sure if the certificate applies to experimental category aircraft though. The only reference I can find about it in the FAR's (61.163) applies to ATP and commercial certificates.

Interesting. I think the V-22 Osprey is such a neat design, it makes sense that it required a whole new class of certificates.

Looks like the Terrafugia TF-X (looks like it's currently in dream phase) might be in this class. (https://www.terrafugia.com/tf-x/)

Moller is still around and still working on prototypes, though whether they can bring something to market is questionable.


text:
Can reverse-thrust be used to push back from the gate?
Crazy idea, I know.  But instead of pushing back a passenger plane using a vehicle connected to the front wheel, what if I turn on the reverse-thrust and rev up the engine?  My logic is if it can slow down the plane during the landing, it can certainly roll the plane from a dead stop having it go backwards to clear the gate.  Would that be possible in terms of laws of physics?

While I rarely see this happen these days, I used to see it all the time back in the 90s, especially on DC-9/MD-80/MD-90 type aircraft, but also on the older 737s that had low-bypass engines.

Some airports do this all the time. It is noisy.

It has been done before but is generally frowned upon due to high fuel consumption, equipment FOD caused by debris kicked up by the fan exhaust and intake suction dangers.  It is just simpler and safer to connect a powered tug and give the aircraft a pushback.
But yes, you can pushback using thrust reversers.

It's worth noting that there's a separate, specific term for this procedure: It is called a powerback, and the safety issues been discussed on this site in a separate question

Not being a pilot, I might be wrong, but here goes
Theoretically yes, but a pilot usually only uses reverse thrust above a certain speed, because of the danger of debris on the ground being blown forward and sucked into the engine intake. They use reverse thrust to slow down until 80 or 100 knots (IIRC)
Related: Is it possible to use thrust reversers to taxi backwards?

Thanks Vorm.  I wonder how come that's never used in 007 movies.


text:
What are the white circles just before the runway holding point?
What are the white circles before runway holding point? I tried looking on manual but couldn’t find anything

Can you include an illustration or photograph showing what you're referring to?

If you can add in the particular airport you've seen them at, someone might be able to find a photograph.

These white circle were also marked with some range and bearing data. That means if your aircraft is in that circle, your vor and dme should read those marked values which in turn help the pilot to check serviceability/accuracy of vor dme.
It’s manual version of test Vor to check accuracy of aircraft equipment.

Which white circles are "these white circles?"

If they look like this one at KSJC

[https://www.google.com/maps/@37.356458,-121.9258751,158m/data=!3m1!1e3]
then it is a certified VOR receiver checkpoint.  These will be listed in the chart supplement (A/FD).

San Jose (Norman Y. Mineta San Jose Intl) 114.1/SJC G 125 1.4 On runup
  area Twy W and D.

The Standards for Airport Markings should have information on all markings for US airports.  It has this information on the design and dimensions of VOR checkpoints.


text:
Pilots diploma made in USA-nostrification in Europe. How it works -what are the procedures?
I am a Polish citizen and am presently enrolled in flight training in USA.
Upon graduation, I will have approximately 250 hours of flight time and the following certificates and ratings:

PRIVATE PILOT
INSTRUMENT RATING
COMMERCIAL PILOT
MULTI-ENGINE RATING

In addition I may also have the following:

CERTIFIED FLIGHT INSTRUCTOR (CFI)
CERTIFIED FLIGHT INSTRUCTOR-INSTRUMENT (CFI-I)
CERTIFIED FLIGHT INSTRUCTOR-MULTI-ENGINE (CFM)

I have been led to believe that I may not be able to work in the United States and will have to return to Europe for employment.
How much of this training and experience will be transferable to Europe?
I understand that the ratings would not allow me to immediately be
employed in Europe, but I am hoping that the level of training and experience will at least be of value and can be transferred.
Does anybody know how to nostrificate a diploma from the USA to Europe?
Please advise me as to what I may expect after I finish school in USA and back to Europe what are costs, and what is the time necessary to nostrificate- transform all papers into Europe..
Will it be possible to get a job in USA airlines for not US citizen? on F1 visa?
If not what are the procedures to transfer a diploma to Europe and what is necessary to do it .where to look for help in that case?

The answers to your questions are what you should have researched BEFORE you started spending money on lots of training that might/not be transferrable. In practice, the US CPL is not transferrable to anything usable in Europe - the training is good for you, but the qualification at the end is not. And the CFI/I ratings are not recognised in Europe. You will have a lot to do when you get back, but you will need to talk to your local EASA to get the official words.

Welcome to aviation.SE! The visa question is about immigration so you might get more information at expats.SE. Unfortunately we have very little information on this site about converting FAA to EASA licenses; this question may be the only one. But if you find out more information yourself please feel free to answer your own question, that's completely fine here.


text:
How do landing fees work at larger airports?
Many larger airports (class Bravos) have a landing fee. What's the process for assessing and collecting the fees?

How do these landing fees work with general aviation aircraft?
Where can I find out what the fee will be? Is it published?
How will I be charged the fee? (Pay before leaving the airport, bill sent to my home, etc.)
Is the landing fee a flat rate or is it calculated based on aircraft weight or some other factor?
I've heard that the landing fee is generally waived if you buy a few gallons of (overpriced) gas at an FBO, is that true?

Example scenario: I offer to take a friend up for a scenic flight. He lives very close to a moderately busy class B airport while my home airport and FBO is over an hour away from him. I offer to fly into the class B airport to pick him up and then drop him off at the end of the flight.

Well, the short version is that there really isn't a standard (and this applies to small as well as large airports).

Some airport authorities charge fees that are billed through the FBO, some don't.
Some airport authorities bill you directly, some don't.
Normally you pay at the FBO before you leave.
Most of the FBO's set their own fees (although they may come from corporate).
Some FBO's don't charge any fees (although not very many these days).
Some FBO's waive some (or all) of their fees if you buy fuel, some don't.
Most FBO's charge a fee based on the size/class/weight of aircraft, some don't.

In short, call ahead to the FBO that you will be using and ask them what the fees are and whether or not any of them can be waived.  They are used to this question and will have the information handy for you.

Some of the FBO's that have websites will list their prices there as well but I have found this to be a hit or miss case.

There are some airports (such as the major ones in the NYC area) that have ridiculous landing fees even for small aircraft.  I asked the Port Authority guy about this once and he said that they do it do discourage small aircraft from coming to their airport.  They can't legally exclude small aircraft, but they can make their fees so ridiculous that no one other than an airline could afford it.  Best I remember, it was around $200 back then and that was probably 20 years ago.  I figure that if an airport charges a landing fee, they don't want you to come to their airport and I avoid them.  If an airport does not waive the overnight parking fee if I refuel, I don't go to that airport either.  As they say, "Vote with your wallet"...


text:
What frequency should be used for air-to-ground communication other than airport ground operation?
On a VFR flight, what frequency should be used to talk to somebody on the ground in USA?
In another word, if I am overflying my house and I would like to talk to the people on the ground, what frequency should I be using? Is it even legal to do something like this?

850/900/1,800/1,900 MHz?   :)

Radio frequencies in the USA are assigned by the FCC, not the FAA. There's no 'private' air-to-ground frequency mentioned in the AIM but section 4-1-11 does say that the FCC has assigned 122.900 as a MULTICOM frequency for:

Activities of a temporary, seasonal, emergency nature or search and
  rescue, as well as, airports with no tower, FSS, or UNICOM

Arguably your fly-by is "temporary activity", however the definition of MULTICOM is:

A mobile service not open to public correspondence used to provide
  communications essential to  conduct the activities being performed by
  or directed from private aircraft

So if your fly-by is "essential" (and safe!) then I guess you could use 122.9. There are procedures for requesting temporary air-to-ground frequencies for air shows, but that's obviously a special case.
As for legality, it seems that you need an FCC license to use an aviation handheld radio on the ground:

You may only use your hand-held aircraft VHF radio in your aircraft
  under the terms of your aircraft license. You are required to have a
  separate Ground Station license to operate your radio on the ground.

But because this is more about FCC regulations than FAA ones, I suggest that you ask on ham.SE; they'll probably know a lot more about how it all works.

Some people use "fingers" 123.45 for non-standard radio communications. I don't think it conflicts with any existing radio stations and its legality is in in doubt. Sometimes you will hear on a busy frequency "BOB! FINGERS" which is never acknowledge either by the intended recipient or by ATC, but it means t come up on 123.45

FYI the FCC has designated 123.450 MHz for flight test stations: The use of flight test stations is restricted to the transmission of necessary information or instructions relating directly to tests of aircraft or components thereof.

Probably why people use it!


text:
What does the T in RVR-T stand for?
In the Chart Supplement (A/FD) for CRQ/KCRQ, you will find RVR-T for runway 24.
I was wondering what 'T' stands for?

From page 5-1-7, contractions in the AIM:

RVRT . . . . . . . . . RVR Touchdown

The full list is:

RVR . . . . . . . . . . Runway Visual Range
  RVRM . . . . . . . .  RVR Midpoint
  RVRR . . . . . . . . . RVR Rollout
  RVRT . . . . . . . . . RVR Touchdown

On some runways there are multiple RVR sensors and different points along the runway, and these are the names given to identify the different locations.

Runway Visual Range - Touchdown
From FAA 6560.10C

Touchdown RVR VSs are located 0 feet to 2,500 feet (0 meters to 750 meters) from the runway threshold, normally behind the instrument landing system (ILS) glide slope (G/S) antenna, precision approach path indicator (PAPI), visual approach slope indicator (VASI), or microwave landing system (MLS) elevation antenna (if applicable).


text:
Can an encapsulated airfoil generate enough lift to lift the capsule?
Can an airfoil generate enough lift, if it is contained in an enclosed space, to lift the enclosed space?  Assume that there would be sufficient airflow over the foil to generate lift if it was not in an enclosed space to lift the airfoil and the enclosed space if it were externally attached.

This is a bit unclear, but I'd say "no". After all, wings are tested in wind tunnels and the wing doesn't lift the whole tunnel building off the ground.

Does a car get lighter (total weight on wheels decrease) when a bumblebee at rest in the car takes off into flight?  (Assume windows closed.)  Is the answer different if the windows are open?

@quietflyer, how is it akin to perpetual motion?

guess it's not, deleted!\

Where is the air coming from in this enclosed space and where does it go after passing the airfoil?

@jim, TBD. But, it could be recycled within the space, or vented.

@quietflyer, Also, the bumblebee is not attached to anything in the car after take off.  I'm referring to an airfoil fixed within the enclosed space.

If it’s recycled then there will be forces on the enclosure getting it turned around. If it’s vented then it not a closed space anymore

@Jim, see Options 1 and 2 in diagram added to original post.

Clearly this is how the most basic of alien designs, the saucer, stays airborne.

You could just as easily argue that the downwash created by the wings inside the tube would force the entire contraption downwards though, right?

I think Mythbusters covered this one: https://www.youtube.com/watch?v=lVeP6oqH-Qo

Here is my interpretation of the question: Is it possible to build a wind tunnel where the whole tunnel is suspended through upside down wings in the airflow. The wings upwash push against the ceiling holding it up. The walls and floor are then attached to the ceiling..... This is called air bearing.

What stops the whole gadget from rotating? There is unbalanced torque.

@copper.hat I suppose a rotation is the point of many bearings. With the wings it would be an aerodynamic bearing.

If you could create net lift in a closed system, we'd have a serious problem with gyms spontaneously flying away.

Consider Newton’s third law - for any action there is an equal and opposite reaction.  If the action is to lift the enclosure then what is the reaction?  It has to be pushing against something.  You might just as well hope to levitate by pulling your own bootlaces.

Good comparison.  Or pushing up on the inside of a box and expecting the box to rise into the air.

The air going past the airfoil pushes the airfoil up, and goes down. A few moments later, it hits the bottom of the tube, pushing the tube down.

A system like this would also be a reactionless drive and violate the law of conservation of momentum.

Can an airfoil generate enough lift, if it is contained in an enclosed
space, to lift the enclosed space?

If this were possible, the enclosed structure would rise up through the atmosphere without creating any downwash at all.  It's intuitively clear that this would not be possible.
In fact, some upwash would be created by drag on the exterior walls of the enclosed structure as it rises up through the atmosphere.  This would be inconsistent with the principle of conservation of momentum.
If you had the enclosed structure supported above the ground on a stand, and someone came and took away the stand at exactly the same instant the fan inside the enclosed structure started blowing air over the airfoil and (theoretically) creating lift exactly equal to the weight of the enclosed structure ( + airfoil), so that the vertical speed of the enclosed structure remained at zero even with the stand removed, the conservation of momentum argument would no longer apply.  Still, it's intuitively clear that this enclosed structure could not hover above the ground without creating any downwash.

Not sure I follow.  On Wikipedia, downwash is defined as "the change in direction of air deflected by the aerodynamic action of an airfoil, wing, or helicopter rotor blade in motion, as part of the process of producing lift". There is still downwash, it's just contained within the enclosed space.

Well, if you define the "system" as equal to the enclosed space, then there is no downwash extending beyond the boundaries of the "system".  So it seems to me intuitively clear that the "system" as a whole cannot support itself above the ground.  Maybe another answer can explain it better.  But the point is that if the "downwash" from the blades is not leaving the boundaries of the "system", then something--such as the walls of the enclosed space-- is interrupting it.  And that interaction exerts a downward force on the walls of the enclosed space.   Which cancels out the airfoil lift force.

Think of it this way @KevinMcDowell, if you were standing outside this enclosed space, how would you detect that the airfoil inside was producing lift?  Some exterior force would need to act on the structure as a whole to cause it to rise, what would that force be?

@MichaelHall, that's kind of where I was going.  Lift from an airplane wing is not acting against the ground, else we'd feel the downwards pressure of any airplane that passed overhead.  Can enough pressure be generated in a closed system to lift it?  What if the air was compressed?

@quietflyer, what if the system wasn't completely enclosed, like in option 3 (in the image I added to the original post)?

Option 3 could generate lift.  It's a variation on a (vaned) ducted fan.

"Lift from an airplane wing is not acting against the ground, else we'd feel it."  If that was true, then ground effect would vanish.  We humans don't feel it only because the airplane is so high and the downwash so diffuse by the time it reaches us.  https://aviation.stackexchange.com/q/51879/31425

@KevinMcDowell,  Of course there's downwash, have you never seen videos of people getting blasted by the downwash of low flying aircraft?

@KevinMcDowell any downwash contained within the enclosed space will act on the enclosure, negating any lift produced by the wing.

@KevinMcDowell Lift from an airplane wing is acting (eventually) against the ground, therefore, we do feel the downward pressure of airplanes passing overhead. It's just spread out over such a large area that it's barely even measurable.

@KevinMcDowell It acts against the air which acts against the air which acts against the air which acts against the air which acts against the air which acts against the air which acts against the ground. It's just really spread out by the time it gets to the ground.

You need to first understand what is lift in this situation.
In all 3 diagrams. Lift is the force between the airfoil and the enclosed space. The lift will generate a force that pulls the airfoil towards the ceiling of the space and away from the floor. It has nothing to do with the relationship of the enclosed space and the outside world.
This situation is exactly the same as you pulling a rope on the floor:

Is it ever possible to lift the floor you are standing on by pulling on a rope attached to it?
Once you see it this way it is obvious that you cannot lift yourself by pulling on a rope attached to the floor. The only way for it to work is to step outside the floor onto the ground around it - only then can you lift the floor because you are now generating a force (lift) against the ground instead of against the floor.
Similarly, if you fully enclose the air it will not lift the space around it. You need to let the air have access to the space outside the enclosed space in order for it to work because you need to generate lift relative to the outside instead of relative to the enclosed space.

The real problem may be air flow within the container.  But if we put, say, stators on the floor or something to prevent a vortex ring from forming, and the room was infinitely large and light, I wonder.  But having air flow in one end and out the other would be better.

@RobertDiGiovanni The free-body diagram does not change even in that case. How do you lift the floor you are standing on? It is actually kind of possible but only momentarily - using an impulse. You can't lift the floor but you can make it bounce. Imagine instead of pulling on the rope you put a heavy weight on the open end and swing it vertically. With enough energy input you can make the floor bounce from the ground (it's how phone vibrators work). Similarly if you can make the air quickly rush from the floor to the ceiling you can momentarily make the container bounce

@RobertDiGiovanni If you have access to an infinitely large room, you have an infinite amount of air to accelerate downwards and that air can go an infinite amount of time without hitting the room and pushing it back down. Note that we do have an infinitely large room called the universe.

@slebetman (academic pursuit only)  if you had a pulley attached to the cieling?  My interest is in the greater efficiency of the prop vs propwash force down.  Sort of like a turbine that can pull itself into the wind.  But in a closed system, the vortex ring will form.  Interesting the 1 might lift and spin, but way less efficiently than an open system.

This is turning into another "if an airplane was on a treadmill..."

Another way to get to the correct answer of "no" is that all your designs have wing sections in a tube. Any low pressure created on the upper surface of these sections is replicated on the bottom of the tube just above, cancelling any lift generated. What you have made is a venturi, not a lifting device.
btw In option 2 no airflow beyond leakage is possible as there is no outlet. You just pressurize your container.

In short, no.  A aerofoil works by creating a region of high pressure below the wing and low pressure above, this provides lift.
In the enclosed system, we still have high pressure below and low pressure above the aerofoil but countering that we have normal atmospheric pressure above and below the contining tube with both providing a net downward force which equals and cancels the upward force experienced by the aerofoil.

Sure, depending how you define "Lift"
Option 1, no way. You could possibly make it leap into the air by sloshing the air around violently enough, but that's unlikely, unsustainable, and too much of a stretch of the definition.
Option 2, sure. If your wing is near enough to the exit, it could redirect the air down, which will push the system up. It's hard to imagine that providing enough lift to fly.
Option 3, maybe. If you implemented it in a way that drives significant pressure changes, you might be able to get a pressure differential that causes the diffusing structure to lift up.
In both Option 2 & 3 though, the wings basically don't matter. The wind tunnel is acting as an overly-elaborate airfoil.
So. Does that count?

Expanding on @pilothead's answer, remember that the airfoil generates lift by creating a low pressure area above the wing.  This low pressure area isn't just lifting the wing up, it is pulling in air and whatnot from every direction.  The airfoil lift's because it is part of the "whatnot".  In your enclosed space, roof of your enclosure is also part of the "whatnot" and the exact same amount of force placed on the upper surface of the wing is placed on the enclosure above the low pressure area, pulling it downward.
Basically, it means that since the low pressure area is inside the enclosure, it can't lift the enclosure.  You would need a low pressure area above the enclosure in order to lift the enclosure.

Option one is a fully closed system so its center of gravity will not (in steady state) be affected of the internal fans and wings
Since all flow is inward bound in option two it would either go to zero or pressure would go to infinity, so no lift.
But for option three, since the geometry produces circulation around the upwards facing tube-bends, it might actually lift off. Not perhaps because of the wings but rather because of the geometry of the tubing and the fans.


text:
Why is there no alert if shutting down a running engine during flight?
In reference to Flight 235, there is a lot of speculation going on today, and since the flight recorders' data indicate that the running engine was shut down manually, everyone is suspecting that probably the pilots made the mistake to shut down the running engine instead of the faulty engine to attempt a restart.
If that was the case, why can't there be an alert to warn the pilots that they are shutting down the working engine?
In the software world, we attempt to create so many fail safe situations to avoid letting users mistakenly take an action which will kill the process, why can't that be done for a multi-million dollar aircraft where so many lives are at stake?
P.S: I know these are all theories and not any official crash investigation reports but I am curious as to how such suggestions can even be made? Even my radios for radio-controlled airplanes provide many fail safe features.

to be fair, in the software world, there are so many "are you sure?" questions that people rarely pay attention.

According to Aviation Herald - Taiwan's Aviation Safety Council (ASC) stated that the right engine failed and the crew shut down the left engine.

Why can't it be done?  It can!  And it would be immediately followed by a multi-million dollar effort to get this system certified by the FAA.  This sort of change to a currently certified system is very difficult and time-consuming.  It will take accidents like this (if pilot error is indeed found to be the probable cause - we need to give the pilots the benefit of the doubt until the investigation concludes) to bring about the will to make a change.  The old saying is that every regulation is written in blood....

Having looked at the AVHerald and Flight Global very early reports, it seems that even if they had a "click to confirm" or other warning, they still wouldn't have had much time to do anything about it.

I'm favorable to reopen this question. While additional answers should not bring something new, the duplicate reason used for closure doesn't seem fair, the other question is not answering this particular case.

I'd say it is because the plane computer systems are too dumb to work out which engine is working.

Because in an emergency situation you do not want to stand in the way of the pilot.(*)
Whoever designs the system knows that it could fail and it also knows that there are two pilots in the cabin. These pilots have been trained to deal with the emergency, have spent hours and hours in simulators to be ready when something happens, you do not want to treat them as clueless users, you want to treat them as professionals that are doing their jobs.
The system told them that there was a failure, if it would have been a black/white decision the system could have already shut off the engine, but it did not: it lets trained personnel to asses the situation and act accordingly.

*: as fooot correctly points out, you do not want to annoy the pilots with warnings (remember, you just told them an engine is not working!), they may be tempted to preemptively cancel them, causing them to miss other warnings that are actually important.

That makes sense but why cant there be a simple alert about the wrong move even if it does not override pilot's command. Even the best trained operators of a machine can provide a wrong input under duress and an alert to indicate that can't hurt?

because it would need to assume a wrong and a right: if the system would know what is wrong and what is right it would do it, not ask the pilot to intervene.

@Iceman - the whole point is that something has gone wrong. The computer doesn't know if the engine has failed, or if it, the computer has failed... if it tries to ask not knowing which is true, it could make things worse. Better to alert the crew and allow them to make the decision based on all available evidence.

Voice recorder information is not a conclusive way to tell what may have happened to the flight.
When one engine is lost on a twin, you normally reduce power to the other engine to mitigate yaw imbalance.
It is certainly possible to create every kind of "warning" system imaginable. The reason aircraft do not have this is because such systems add complexity, cost and weight. Complexity is a bad thing. The more wires and computers you have running around, the more scope there is for errors and problems. Designers generally try to include only things that have significant importance. Remember, the more time a designer spends on "warning systems", the less time they spend on solving problems like how to make the aircraft more efficient and reliable.
As far as the you-are-turning-off-a-running-engine warning is concerned. By the time the warning was received the engine would be off, so it would be post-facto warning--not very useful. Preventing the crew from turning off the engine and forcing them to "confirm" that is what they want to do would add more time to protocol--a very bad thing for that kind of protocol. Also, adding a confirmation system would involve a lot more complexity and probably another button (have you seen the inside of a cockpit?)
Just to describe a scenario. Let's imagine the aircraft has the old confirm-you-want-to-do-this button. The engine is on fire but still running. They need to turn it off. The system now asks them via what? a voice prompt? "Do you really want to turn off a running engine?" So, now they are looking through the hundreds of buttons in the cockpit for the yes-I-really-want-to-turn-the-engine-off button. While they are doing this the aircraft is hurtling towards the ground at 300 mph with an engine on fire. Then they finally find the button and push it, but nothing happens because the circuit to which the button is attached is defective because it only gets tested once every two years, but of course the flight crew does not know this. All they know is they have pushed the button and for some unknown reason they still can't turn off the engine. Meanwhile the aircraft is hurtling towards the ground at 300 mph with an engine on fire and they have seconds left to figure out what the hell is going on....
Just to re-iterate what Frederico said above: emergency systems should not get in the way of the pilot, so any system, no matter how "perfect" it is, that prevents the crew from taking control actions because it is second guessing that action is generally looked on as creating more risk, not less risk.

Voice recorder information actually there is already some FDR data, but no reports.

Yep I have :) And your answer makes sense too but it kinda  over exaggerates the complexity that will be required for such an alert.

@Iceman have you taken into consideration the idea that instead it might be you that are oversimplifying it?

Yes that's very well possible. But then that's the reason I asked because I'm just a student trying to learn more about it. Not trying to be authoritative nor do I intend to say that my idea is surely right. Trying to debate and learn

In a previous case where a pilot shut-down the wrong engine, the main recommendations concerned pilot training and clarity of cockpit information.
There doesn't seem to have been any desire to develop ever more complex systems that obstruct pilot actions in an emergency.
From AAIB report on 737 crash at Kegworth, UK 1989